Room environments are challenging for transmission of information via acoustic signals. This is due to the extreme multi-path nature of an impulse response of the room from the transmission source (loudspeaker) to wherever the capture device (microphone) resides. Although humans are well adapted for this environment, traditional forms of communications (e.g. using acoustic tones and pulses) have difficulty operating reliably in such an environment. As an example, direct path sound may be as much as 20 dB below a sum of reverberant sound (non-direct path sound) when the loudspeaker and the microphone are separated by 30 feet in a typical conference room. Proximity pairing of endpoint devices is used to associate the endpoint devices with each other prior to establishing a communication session between the devices. Proximity pairing involves an exchange of signals between the endpoint devices to be paired, but the exchange of signals often suffers from the extreme multi-path mentioned above, which may prevent appropriate pairing, or possibly result in inappropriate pairing.